High surfaces, which represent dead space, are commonly advantageously used for storage of objects of various different types. For example, it is common for rescue ladders and folding boats to be mounted on the top of firefighting vehicles; and for these devices to be used in rescuing people. However, each time that such objects are loaded or taken down from these high places, it is necessary to go up to this high surface and pass the objects up and down, which is troublesome and may be dangerous. There is a particular problem in the case of ladders and boats for rescue purposes mounted on the top of vehicles, since it is not possible to take these down quickly, even if there is an urgent need to use the ladder or boat.
Lift devices can also be used for loading and unloading non-emergency objects. Conventional lift devices for such use generally use hydraulic systems or the like to move loading platforms straight up and down. With such conventional type of lift device, it is necessary for a person to move the objects between the loading platform and the high surface. Furthermore, crane systems are capable only of reducing human labor, and cannot be expected to greatly reduce the time required for loading and unloading, and so these systems are not suitable for firefighting and the like, where speed is important.
Japanese Patent No. JP-3380199-B and Japanese Laid Open Patent Application No. JP-2004-182363-A describe the development and use of a lift device in which a long carrier that bears various types of objects is lowered at an inclination from a high surface, such as the top of a vehicle, by swinging (rocking up and down) a swing arm. However, while the lift device of Japanese Patent No. JP-3380199-B is useful in that it allows objects such as rescue ladders used by firefighting vehicles and the like to be quickly and easily loaded or unloaded without going up onto the top surface of the vehicle, when the length of the carrier is increased to accommodate the loading of long objects, the length of the swing arm (which corresponds to the boom in the present invention) must be increased by a corresponding amount. This presents a problem in that the swing radius of the swing arm increases so that, when working in an enclosed space having a low ceiling or beneath overhead wires, the swing arm or the top of the carrier may collide with obstacles such as ceilings or overhead wires when the swing arm is swung.
With respect to this problem, in Japanese Laid Open Patent Application JP-2004-182363-A, problems such as those described above are solved by providing a configuration wherein the swing arm telescopes during the swing so that the length thereof is reduced when in the upright posture. The center of swing of the swing arm is on the top of the vehicle, and the swing arm only swings up and down directly above the top of the vehicle, so that even if the length of the swing arm is increased, if the carrier is short, it is not possible for that carrier to hold long objects and if the vehicle is high, with respect to the length of the carrier, it is not possible to lower the carrier to a position at which objects can be removed.
The present invention is a reflection of the situation described above, and accordingly, an object of the present invention is to provide a novel lift device and a vehicle equipped with the same, capable of suitably lowering objects placed in a high position to a predetermined lower position that can be reached by people.